* Set but unused variable in Parser/pgen.c in non-debug builds. Patch by
Christian Heimes.
* Unused static function in Modules/readline.c. Patch by Georg Brandl.
* main_window unused in Modules/tkappinit.c. Patch by Gregory P. Smith.
* Dead assignment in Modules/_ctypes/cfield.c. Extracted from patch by Brett
Cannon.
* Expression result unused in PyObject_INIT macro expansions. Based on
patches by Christian Heimes.
* Load expat_config.h and therefore pyconfig.h before C stdlib headers are
loaded. This silences pre-processor warnings including '_POSIX_C_SOURCE
redefined'. Extracted from patch by Christian Heimes.
* Now the source encoding declaration on the second line isn't effective if
the first line contains anything except a comment. This affects compile(),
eval() and exec() too.
* IDLE now ignores the source encoding declaration on the second line if the
first line contains anything except a comment.
* 2to3 and the findnocoding.py script now ignore the source encoding
declaration on the second line if the first line contains anything except
a comment.
